When a 55-year-old woman with lung cancer saw him in April 2010, prominent oncologist Ang Peng Tiam told her there was a "70 per cent chance" of the disease responding to treatment and achieving control with chemotherapy and targeted therapy.
Dr Ang, who is the medical director of Parkway Cancer Centre, did not offer her the option of surgery, which he felt was not viable in this case due to, among other things, the location of the fist-sized tumour.
The patient died six months later, after the cancer spread to other parts of her body, including her brain, liver and pancreas.
Her family complained about Dr Ang to the profession's watchdog - the Singapore Medical Council (SMC) - which brought four charges against him for professional misconduct.
Last year, Dr Ang was fined $25,000 after a disciplinary tribunal found him guilty of two charges - for falsely representing to the patient her chances of a favourable response to his prescribed therapy and for failing to offer her the option of surgery. He was cleared of the other two charges.
Yesterday, Dr Ang, who is also chief executive of medical oncology firm TalkMed, appealed against his conviction before a Court of Three Judges.
The SMC cross-appealed, arguing that he should be suspended for at least six months per charge.
Dr Ang, represented by Senior Counsel Edwin Tong, argued that it was reasonable for him to cite a 70 per cent disease-control rate just based on chemotherapy alone.
He cited medical literature to support his assertion that the patient's chances would be optimised by combining chemotherapy with anti-cancer drugs called tyrosine kinase inhibitors. This was because the patient had four characteristics - including having never smoked - and such patients have been shown to be highly responsive to the therapy, he argued.
As for surgery, Dr Ang argued that he had made a judgment call that it was not a viable treatment option. Surgery cannot guarantee the complete removal of the tumour, given its size and location, he said.
But the SMC's lawyer Melanie Ho charged that Dr Ang's statement on the 70 per cent chance was false as it is achievable only for patients who test positive for epidermal growth factor receptor mutation.
As he did not carry out the test, Dr Ang had no basis to promise a 70 per cent chance of shrinkage and control of the tumour, she said.
She noted that Dr Ang had not produced literature to support his contention of a 70 per cent chance based on chemotherapy alone.
Ms Ho argued that it was not for Dr Ang to decide on the treatment but to offer options. "It is the patient's right to choose," she said.
After nearly five hours of arguments, the court reserved judgment. A decision will be given at a later date.